Study objectives <p>Sleep deprivation related changes in brain connectivity have been poorly characterized but have important implications for delirium patients and shift workers. This study aimed to describe the functional and effective brain connectivity changes after acute sleep deprivation (ASD).</p> Methods <p>A systematic search of OvidSP Embase, PubMed, and Web of Science databases was conducted for studies published between January 1, 1947, to September 11, 2024. Selected studies examined brain connectivity strength or topology, estimated by electroencephalography, functional magnetic resonance imaging, functional near-infrared spectroscopy, magnetoencephalography, or positron emission tomography, after ASD. Data extracted from eligible studies included primary outcomes: functional neuroimaging modality, type of brain connectivity analyses and results of brain connectivity analyses. Studies were grouped for synthesis based on functional neuroimaging modality and connectivity measures.</p> Results <p>The search produced 1015 articles. 357 duplicates were removed, and 658 articles were screened. Of these, 250 underwent full-text review and 141 were excluded. This produced 109 articles for review. Results demonstrated that the methodology and analyses employed to study functional and effective connectivity after ASD were heterogeneous. However, despite this heterogeneity, studies demonstrated that ASD leads to robust and consistent alterations in the functional/effective connectivity of multiple brain networks, particularly the default mode network.</p> Conclusions <p>This review summarizes the key functional and effective connectivity changes associated with ASD. This work will serve as a reference and resource for researchers and clinicians focused on delirium and related conditions, in addition to those interested in ASD and shift work.</p>